Messages in this thread | | | Subject | Re: computing drop-able caches | From | Daniel Walker <> | Date | Fri, 29 Jan 2016 13:21:47 -0800 |
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On 01/28/2016 05:55 PM, Johannes Weiner wrote: > On Thu, Jan 28, 2016 at 05:29:41PM -0800, Daniel Walker wrote: >> On 01/28/2016 05:03 PM, Daniel Walker wrote: >> [regarding MemAvaiable] >> >> This new metric purportedly helps usrespace assess available memory. But, >> its again based on heuristic, it takes 1/2 of page cache as reclaimable.. > No, it takes the smaller value of cache/2 and the low watermark, which > is a fraction of memory. Actually, that does look a little weird. Rik? > > We don't age cache without memory pressure, you don't know how much is > used until you start taking some away. Heuristics is all we can offer.
With a simple busybox root system I get this,
MemTotal: 16273996 kB MemFree: 16137920 kB MemAvailable: 16046132 kB
shouldn't MemAvailable be at least the same as MemFree ? I changed the code somewhat so it subtracted the wmark_low only, or the pagecache/2 only, both are still under MemFree. This system has very little drop-able caches.
Daniel
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